Native ZFS Encryption in TrueNAS

  6 minute read

You can encrypt the root dataset of a new storage pool to further increase data security. Please note that you will be responsible to remember or otherwise back up passphrases or other access methods to your encrypted data.

Data-at-rest encryption is available with:

Keys for data-at-rest are managed on the local TrueNAS system. The user is responsible for storing and securing their keys. The Key Management Interface Protocol (KMIP) is included in TrueNAS 12.0.

Encrypting a Storage Pool

To begin encrypting data, follow the same process as creating a new pool and set the Encryption option at the top of the page.

Check the Encryption box, read the Warning, click the Confirm box and then click the I Understand button.

The default encryption cipher is recommended, but there are other ciphers available.

Encrypting a New Dataset

New datasets within an existing storage pool can also be encrypted without having to encrypt the entire pool. To encrypt a single dataset, go to Storage > Pools, open the   (Options) for an existing dataset, and click Add Dataset. Look at the Encryption Options and, if the parent dataset is unencrypted, unset the Inherit option.

You can then set Encryption for the new dataset and choose which Type of authentication to use: a Key or a Passphrase. Encryption options are the same for either a new pool or dataset.


Creating a new encrypted pool automatically generates new key file and prompts to download it. Always back up the key file to a safe and secure location.

Manually back up a root dataset keyfile by opening the pool (Settings) menu and selecting Export Dataset Keys.

To change the key, click   (Options) and select Encryption Options.

Enter your custom key or click Generate Key. Remember to back up your key files after creating or updating them.


To use a passphrase instead of a keyfile, click   (Options) and select Encryption Options. Change the Encryption Type from Key to Passphrase.

Encryption Type: How the dataset is secured. Choose between securing with an encryption Key or a user-defined Passphrase.

Passphrase: User-defined string used to decrypt the dataset. Can be used instead of an encryption key. WARNING: the passphrase is the only means to decrypt the information stored in this dataset. Be sure to create a memorable passphrase or physically secure the passphrase. Must be longer than 8 characters.

pbkdf2iters: Number of password-based key derivation function 2 (PBKDF2) iterations to use for reducing vulnerability to brute-force attacks. Entering a number larger than 100000 is required. See PBKDF2 for more details.

Locking and Unlocking Datasets

Status of a dataset can be determined based on the icon used after the name.

Dataset Unlocked Icon :

Dataset Locked Icon :

Encrypted datasets can only be locked and unlocked if they are secured with a passphrase instead of a keyfile. Before locking a dataset, verify that it is not currently in use, then click   (Options) and Lock.

Use the Force unmount option only if you are certain that no one is currently accessing the dataset.

A dialog window remains visible while the dataset is locked.

After locking a dataset, the unlock icon changes to a locked icon. While the dataset is locked, it is not available for use.

To unlock a dataset, click   (Options) and Unlock.

Enter the passphrase and click Submit. If there are child datasets that are locked with the same passphrase you can unlock them all at the same time by setting Unlock Children.

Confirm that you want to unlock the datasets.

A dialog confirms when datasets are successfully unlocked.

The dataset listing changes to show the unlocked icon.

Conversion from GELI

It is not possible to convert an existing FreeNAS/TrueNAS 11.3 or earlier GELI-encrypted pool to use native ZFS encryption.

Migration from GELI

Data can be migrated from the GELI-encrypted pool to a new ZFS-encrypted pool. Be sure to unlock the GELI-encrypted pool before attempting any data migrations. The new ZFS-encrypted pool must be at least the same size as the previous GELI-encrypted pool. Two options exist to migrate data from a GELI-encrypted pool to a new ZFS-encrypted pool: file transfer or ZFS send/receive.

In future TrueNAS versions, a decrypted GELI pool will be able to migrate data to a new ZFS encrypted pool using an advanced Replication Task (NAS-107463). Until this time, GELI encrypted pools will continue to be detected and supported in the TrueNAS web interface, so you are not required to immediately migrate data away from GELI pools. Before using the command line to migrate data, it is recommended to consider the benefits and drawbacks of immediately migrating from GELI to ZFS.

ZFS data migration can be a complicated process. You can ask for assistance in the TrueNAS Community Forums or, if you have a support contract with iXsystems, contact iX Support for assistance.

File Transfer

The first method is to use rsync or other file transfer mechanisms (scp, cp, sftp, ftp, rdiff-backup) to copy the data between the pools.

ZFS Send and Receive

The second method is to use ZFS send/receive commands.


GELI Pool = pool_a
Origin Dataset = dataset_1
Latest Snapshot of GELI Pool = snapshot_name
ZFS Native Encrypted Pool = pool_b
Receieving Dataset = dataset_2
  1. Create a new encrypted pool in Storage > Pools, as described at the beginning of this article.
  2. Open the Shell. Make a new snapshot of the GELI pool and dataset with the data to be migrated: zfs snapshot -r pool_a/dataset_1@snapshot_name.
  3. Create a passphrase: echo passphrase > /tmp/pass.
  4. Use ZFS send/receive to transfer the data between pools: zfs send -Rv pool_a/dataset_1@snapshot_name | zfs recv -o encryption=on -o keyformat=passphrase -o keylocation=file:///tmp/pass pool_b/dataset_2.
  5. When the transfer is complete, go to Storage > Pools and lock the new dataset. After locking the dataset, immediately unlock it. TrueNAS prompts for the passphrase. After entering the passphrase and the pool is unlocked, you can delete the /tmp/pass file used for the transfer.
  6. If desired, you can convert the dataset to use a keyfile instead of a passphrase. To use a passphrase instead of a keyfile, open the dataset   (Options) and click Encryption Options. Change the Encryption Type from Passphrase to Key and save. Remember to back up your keyfile immediately!
  7. Repeat this process for every dataset in the Pool that needs to be migrated.

Last modified January 19, 2021: fix support link (1fc10d0f)